CN1092080C - Catalyst and process for producing unsaturated aldehyde and unsaturated acid - Google Patents

Abstract

A catalyst for the production of unsaturated aldehydes and unsaturated acids, which is obtained by calcining the supported catalyst after the catalytically active component is loaded on the carrier. It is characterized in that the average particle diameter of the catalyst is 4-16mm, and the The average particle size is 3-12mm, the calcining temperature is 500-600°C and the amount of the catalytically active component loaded on the carrier is 5-80% (wt) [(the weight of the catalytically active component)/(the weight of the catalytically active component weight+carrier weight+strength improver weight)], and the method for producing unsaturated aldehyde and unsaturated acid with catalyst of the present invention.

Description

A kind of catalyst and method for producing unsaturated aldehyde and unsaturated acid

The present invention relates to a method for producing unsaturated aldehydes and unsaturated acids and a catalyst used in the method.

The catalytic oxidation of olefins with 3 or 4 carbon atoms to the corresponding unsaturated aldehydes and unsaturated acids using various mixed oxide catalysts containing molybdenum, bismuth and iron in the gas phase has been proposed, some of which have been used in used on an industrial scale. Examples of these catalysts include those described in Japanese Patent Laid-Open Nos. 27490/1972, 42241/1972, 1645/1973 and 61011/1982 and the like.

However, the production of unsaturated aldehydes or both unsaturated aldehydes and unsaturated acids on an industrial scale in the presence of such catalysts poses various problems.

One of these problems is the formation of locally abnormally heated portions (hot spots) in the catalyst bed. The hot spot is formed because the gas phase catalytic reaction is exothermic. In order to increase the productivity of unsaturated aldehydes and unsaturated acids on an industrial scale, it is common practice to increase the concentration of raw olefins or to increase the space velocity.

However, under such a high load reaction condition, the heat generated by the hot spot increases, which shortens the life of the catalyst, and the oxidation reaction is excessive, and the biggest problem is that the reaction is out of control.

Although the common practice is to settle for low productivity or take precautionary measures, such as reducing the diameter of the reaction tube, to reduce the formation of hot spots or reduce the abnormal heat generated at hot spots. However, doing so is economically disadvantageous.

Various studies have been conducted and reported to be safely and economically produced on an industrial scale while avoiding hazards arising from hot spots in reaction operations. So far, proposed methods include, for example, a method of diluting the catalyst by mixing an anti-hot spot formation catalyst, that is, an inert substance (Japanese Patent Laid-Open No. 10614/1972) and a method of using a tubular catalyst (Japanese Patent Publication No. 36739/1987). In addition, the following method has also been proposed: a method of forming two reaction zones in a reaction tube (Japanese Patent Laid-Open No. 127013/1976), in the oxidation reaction of propylene, by changing the composition of the catalyst (especially the type of alkali metal and /or dosage), produce two or more than two kinds of catalysts with different activities, add the reaction tube along the axis of the reaction tube, the method that the activity of the catalyst increases gradually along the direction of the feed gas inlet to the outlet (Japanese Patent Publication 38331/ 1988) and adding catalysts with different space occupations into the reaction tube so that the space occupied by the catalyst decreases gradually from the inlet side to the outlet side of the reaction tube, forming two or more reaction zones along the axial direction of the reaction tube ( Japanese Patent Laid-Open No. 217932/1992).

However, in the method in which the catalyst is dilute with an inert substance, the time taken for adding the catalyst to the reactor during periodic maintenance of the equipment increases because the inert substance used for dilution is uniformly mixed with the catalyst before the addition. In addition, in this method, since uniform mixing is always impossible, hot spots are slightly increased in the catalyst-high-concentration portion. Another disadvantage of this method is that in each reaction tube, the position and temperature of the hot spot are different from each other, which is inconvenient for the reaction operation. Therefore, this method is unlikely to be satisfactory for controlling the increase in heat generation at hot spots.

Under high-load reaction conditions of high concentration feedstock and high space velocity, the method of controlling catalytic activity using tubular catalysts is also not obvious for controlling the formation of hot spots.

The method of controlling the catalytic activity by changing the type and/or amount of the alkali metal also has disadvantages, that is, because the amount of the alkali metal used is far smaller than the amount of other components, increasing or decreasing the catalytic activity by adding an alkali metal is like a catalyst. Manipulation in preparation is difficult as large. Furthermore, for other components used in large amounts, it becomes more difficult to control the catalytic activity by the influence of the alkali metal contained in the raw material.

In a method in which catalysts with different space occupations are added to the reaction tube from the inlet side of the reaction tube to the outlet side, the space occupied by the catalyst is gradually reduced to form two or more reaction zones along the axis of the reaction tube , an extremely complicated operation is necessary to add the catalyst, and in the periodical maintenance of the equipment, the time required for adding the catalyst increases. From an economic point of view, this is very disadvantageous in operation on an industrial scale.

An object of the present invention is to provide a method for efficiently producing unsaturated aldehydes and unsaturated acids by solving the above-mentioned problems of the prior art, and also to provide a catalyst suitable for the method.

More specifically, the object of the present invention is to provide a method for the production of unsaturated aldehydes and unsaturated acids by gas-phase catalytic oxidation of olefins or tertiary alcohols under high-load reaction conditions, wherein in the catalyst bed, super The heat generated by the hot spot is controlled without requiring any complicated feeding operation as in the prior art, so as to obtain a high yield of the target product, and by preventing the deactivation of the catalyst caused by the heat load, a stable reaction can be continued continuously for a long time.

In exothermic reactions like the gas-phase catalytic oxidation reactions described above, the catalytically active components have been shaped in various ways in the prior art, the shaped articles mainly comprising the catalytically active components. Assuming that the catalyst is the location where the gas phase catalytic oxidation reaction takes place, heat generation occurs right on the catalyst. Therefore, when a shaped catalyst is used for a reaction, the heat generated by the reaction is concentrated in the catalyst, inducing the formation of hot spots. In order to reduce the apparent density of the catalytically active component and avoid the heat generated by the reaction from being concentrated on the catalyst, after thorough and meticulous research, the inventors have found that by controlling the amount of the catalytically active component loaded on the inert carrier, the catalyst The particle size and calcination temperature can achieve the above purpose. The present invention has been accomplished on the basis of this discovery.

Therefore, the present invention relates to the preparation of a catalyst by loading a catalytically active component on a carrier, and then calcining the supported catalyst, characterized in that the particle diameter of the catalyst is 4-16 mm, the average particle size of the carrier is 3-12 mm, and the calcining temperature It is 500-600 ℃, and the amount of the catalytically active component loaded on the carrier is 5-80% (wt) [(the weight of the catalytically active component)/(the weight of the catalytically active component+carrier weight+strength improver weight)]. The catalyst of the invention is preferably an oxidation catalyst.

The catalyst of the present invention, wherein the catalytically active component preferably has a composition represented by the following formula (1):

Mo _a Bi _b Ni _c Co _d Fe _f Y _g Z _h O _x (1)

In the formula, Y represents at least one element selected from Sn, Zn, W, Cr, Mn, Mg, Sb and Ti; Z represents at least one element selected from K, Rb, Tl and Cs;

a, b, c, d, f, g, h and X respectively represent the atomic number of Mo, Bi, Ni, Co, Fe, Y, Z and O, if a=12, b=0.1-7, then preferably b =0.5-4, c+d=0.5-20, preferably c+d=1-12, f=0.5-8, preferably f=0.5-5, g=0-2, preferably g=0-1, h= 0-1, preferably h=0.01-0.5,

x is a variable that depends on the degree of oxidation of the metal component.

Moreover, the present invention also relates to the production of corresponding unsaturated aldehydes and/or unsaturated acids by gas-phase catalytic oxidation of at least one compound selected from propylene, isobutene and tert-butene with molecular oxygen or a gas containing molecular oxygen. A method for saturated aldehydes and unsaturated acids, characterized by using the above-mentioned catalyst.

The present invention particularly relates to a method for producing unsaturated aldehydes and/or unsaturated acids, characterized in that said catalyst is added to each tube of a fixed-bed multi-tube reactor to form a catalyst bed.

Now, the present invention will be described in detail.

The catalyst of the present invention is prepared by loading the catalytically active component on a carrier and calcining it. The kind of constituent elements of the catalytically active component used in the preparation of the catalyst of the present invention is not particularly limited as long as it is the same as the metal element of the catalytically active component of the catalyst generally used for gas-phase catalytic oxidation of olefin or tertiary alcohol. Among these catalysts, those represented by the above formula (1) are preferable.

The catalytically active component is prepared by methods known per se, such as co-precipitation, and the raw materials used in this method are not particularly limited, such as nitrates, ammonium salts of metal elements constituting the catalytically active component , Hydroxide, etc. Before the catalytically active component is loaded on the carrier, it can usually be calcined at 200-600° C. for 2-7 hours to form a pre-calcined powder. Pre-calcination is carried out under air or nitrogen flow.

In precalcined powders on carriers, styling aids and/or strength improvers are preferably used. Forming aids usable herein include crystalline cellulose, starch and stearic acid. The amount of forming aid used is generally preferably 30% (wt) or less, calculated on the basis of the weight of the pre-calcined powder. Examples of the strength improver used herein include ceramic fibers, carbon fibers and whiskers. The amount of the strength improver is usually 30% (wt) or less, calculated on the basis of the weight of the pre-calcined powder. As mentioned above, the forming aid and/or strength improver can be mixed with the pre-calcined powder before or after the pre-calcined powder and other materials are added to the shape before or when the catalyst active component is loaded on the carrier, so The molding machine has been described previously.

A binder is also preferably used in the precalcined powder on a carrier. Examples of the binder usable herein include water, polymer binders such as polyvinyl alcohol, inorganic binders such as silica sol and alumina sol, polyhydric alcohols such as ethylene glycol and glycerin, and mixtures thereof.

The amount of binder used is typically 10-60% of the pre-calcined powder.

The shape of the carrier is not particularly limited. For example, the carrier can be spherical, cylindrical or tubular. From the viewpoint of production efficiency and mechanical strength of the catalyst, a spherical shape is preferable. The average particle size of the carrier is properly determined according to the inner diameter of the reaction tube and the amount of the catalyst charged therein and the catalytically active component supported, usually 3-12mm, preferably 3.5-9mm, most preferably 3.7-7mm.

Any support that is inert and porous or can be formed into porous particles can be used. Examples of materials that can be used as the carrier include α-alumina, silicon carbide, pumice, silica, zirconia and titania.

The catalytically active component can be coated on the support by any known method capable of uniformly loading the component on the support, such as drum granulation, a method using a centrifugal fluidized coater, or wash coating. Considering the production efficiency of the catalyst, the drum granulation method is preferred. Specifically, in this preferred method, a disc device having a smooth or rough surface at the bottom of a fixed cylindrical vessel is used, and the disc is vigorously stirred by its own rotation and revolution with the carrier added to the vessel such high-speed rotation. If necessary, catalytically active components and binders, forming aids and strength improvers are added to the powder components supported on the carrier. The amount of the active component that changes according to the internal diameter of operating condition such as reaction tube is usually 5-80% (wt), preferably 10-60% (wt), is most preferably 30-50% (wt) [catalytically active component weight/(catalytically active component weight+support weight+strength improver (optional component))] (hereinafter referred to as catalyst loading). The term "weight of catalytically active component" refers to the weight of the precalcined powder. Since drum granulation is the preferred way of producing the catalyst of the present invention, almost 100% of the predetermined amount of pre-calcined powder (or also containing forming aids and/or strength improver powders) can be supported on the carrier.

Then, the catalyst of the present invention is obtained by calcining the catalytically active powder loaded on the carrier. The calcining temperature, which varies according to operating conditions, is generally 500-600°C, preferably 520-560°C. Calcination time is 3-30 hours, preferably 4-15 hours. The particle diameter of the catalyst, which varies with the inner diameter of the reaction tube, the average particle diameter of the carrier and the loading rate of the catalyst, is usually 4-16 mm, preferably 4-10 mm, most preferably 4-7 mm. The particle size of the calcined catalyst is substantially equal to that before calcination.

The production method of the present invention is described in detail below.

In the production method of the present invention, a fixed bed type multi-tubular reactor is generally used, and the length of the packed catalyst, the inner diameter of the reaction tube and the number of tubes vary with the reaction conditions. Therefore, the loading rate of the catalyst, the calcination temperature, and the particle size of the catalyst are appropriately determined in order to obtain an optimum yield. For example, when the inner diameter of the reaction tube is 21-28mm, then the loading rate of the catalyst is preferably 20-50% (wt), the particle size of the catalyst is preferably 4-8mm and the calcination temperature is preferably 500-580°C.

The catalyst of the present invention is preferably used for the gas-phase catalytic oxidation of olefins or tertiary alcohols to produce corresponding unsaturated aldehydes and unsaturated acids, and more preferably to produce acrolein and acrylic acid or methacrolein or methyl from propylene, isobutene or tertiary alcohols acrylic acid.

In the present invention, the gas-phase catalytic oxidation reaction can be carried out by a general one-pass method or a cycle method, which is carried out under the conditions usually used for such reactions, only using the catalyst of the present invention. In the reaction tube, one layer is preferably formed by adding the catalyst of the present invention (one-layer charge). When producing acrolein from propylene, one-stage loading is preferred.

For example, when at least one compound is selected from propylene, isobutene and tertiary alcohol as a raw material, the method of the present invention is to introduce the mixed gas into the reaction tube filled with the catalyst of the present invention, and carry out under the following conditions, the mixing The gas comprises 1-10% (v), preferably 4-9% (v) of feed gas, 3-20% (v), preferably 4-18% (v) of molecular oxygen, 0-60% (v), Preferred 4-50% (v) water vapor, 20-80% (v), preferably 30-60% (v) inert gas (such as N ₂ or CO ₂ etc.), described condition is space velocity (two The raw material gas flow rate/the apparent volume of the loaded catalyst) is 300-5000/hour, preferably 800-2000/hour, the temperature is 250-450° C., and the pressure is atmospheric pressure-10 atmospheric pressure.

In the presence of the catalyst of the present invention that is loaded to form one layer, the oxidation reaction is carried out by olefin or the like, and the following results are obtained:

(a) The temperature of the hot spot can be kept very low to avoid the risk of a runaway reaction caused by an abnormal temperature rise.

(b) It can prevent the excessive reaction of the hot spot, obtain the target unsaturated aldehyde and unsaturated acid in high yield, and have high selectivity to it.

(c) The catalyst can be prevented from deteriorating due to heat load, and the catalyst can be used stably for a long time.

(d) Since the intended unsaturated aldehydes and unsaturated acids can be produced under high-load reaction conditions such as high concentrations of raw materials and high space velocities, the productivity is remarkably improved.

(e) the pressure loss in the catalyst bed can be kept low, and

(f) Since multi-layer loading is not necessary, the time taken for catalyst loading during periodic maintenance of the plant is significantly reduced.

Thus, the catalysts and methods of the present invention are useful in the production of unsaturated aldehydes and unsaturated acids.

Example

The invention is further illustrated by the following examples.

In these examples, conversion, selectivity and yield per pass are defined as follows:

Conversion rate (mol%)=(the number of moles of reaction raw materials)/(the number of moles of raw materials)×100

Selectivity (mol%)=(generates the number of moles of unsaturated aldehyde or unsaturated acid)/(the number of moles of reaction raw materials)×100

Yield (%)=(moles of unsaturated aldehydes or unsaturated acids)/(moles of raw materials added)×100

The preparation of embodiment 1 catalyst

Under heating and stirring, 423.8 g of ammonium molybdate and 2.02 g of potassium nitrate were dissolved in 3000 ml of distilled water to obtain a solution (A). Separately, 302.7 g of cobalt nitrate, 162.9 g of nickel nitrate and 145.4 g of iron nitrate were dissolved in 1000 ml of distilled water to obtain a solution (B). 164.9 g of bismuth nitrate was dissolved in 200 ml of distilled water acidified with 25 ml of concentrated nitric acid to obtain a solution (C). After mixing solutions (B) and (C) together, the resulting solution was dropped into solution (A) under vigorous stirring.

The solution thus obtained was dried with a spray drier, and precalcined at 440° C. for 3 hours to obtain 570 g of a precalcined powder. 200 g of this powder was mixed with 10 g of crystalline cellulose as a molding aid.

300 g of an alumina support having an average particle size of 4 mm was charged into the drum granulation coater. Then the mixture obtained above and the glycerin solution of 90g 33% as binding agent are added in the drum granulation coating machine simultaneously, the mixture is carried on the carrier, thus obtaining a catalyst loading ratio of 40% ( wt) (hereinafter referred to as "active ingredient-carrying particles").

The catalyst (1) of the present invention was obtained by drying the particles carrying the active component at room temperature for 15 hours and then calcining at 520° C. for 5 hours in an air stream. The average particle diameter of the catalyst thus obtained was 4.5 mm, and the atomic ratio of the catalytically active components other than oxygen was as follows: Mo = 12: Bi = 1.7: Ni = 2.8: Fe = 1.8: Co = 5.2: K = 0.1. oxidation reaction

1300ml of the above-prepared catalyst (1) was added to a stainless steel (SUS304) with an average inner diameter of 21mm and provided with a jacket for circulating molten salt as a heat transfer medium and a thermocouple on the catalyst bed for measuring the temperature of the catalyst bed reactor. A mixed gas comprising 8% (v) propylene, 14% (v) oxygen, 25% (v) water vapor and 53% (v) nitrogen was introduced into the reaction tube at a space velocity of 1300/hour while maintaining the molten salt at 334°C react at a temperature. During the reaction, the temperature of the hot spot (the highest reaction temperature point) was 416°C, the conversion rate of propylene was 97.2%, the yield of acrolein was 80.3%, the yield of acrylic acid was 9.9%, and the total selectivity of acrolein and acrylic acid was 92.8%. Even after continuous reaction for 1000 hours or more, no deterioration of the reaction result was found.

Example 2

The reaction was carried out in the same manner as in Example 1, except that the calcination temperature of the particles carrying the active component was changed to 540°C [catalyst (2)], and the temperature using this catalyst and molten salt was changed to 365°C. The hot spot temperature was 424°C, the conversion of propylene was 98.4%, the yield of acrolein was 80.4%, the yield of acrylic acid was 10.4% and the overall selectivity of acrolein to acrylic acid was 92.3%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 3

The reaction was carried out in the same manner as in Example 1, except that the space velocity was changed to 1600/hour and the temperature of the molten salt was changed to 349°C. The hot spot temperature was 457°C, the conversion of propylene was 98.0%, the yield of acrolein was 77.0%, the yield of acrylic acid was 12.9%, and the overall selectivity of acrolein to acrylic acid was 91.7%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 4

The reaction was carried out in the same manner as in Example 2, except that the space velocity was changed to 1600/hour and the molten salt temperature was changed to 360°C. The hot spot temperature was 415°C, the conversion of propylene was 97.1%, the yield of acrolein was 81.5%, the yield of acrylic acid was 8.9% and the overall selectivity of acrolein to acrylic acid was 93.1%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 5

The reaction was carried out in the same manner as in Example 1, except that the calcination temperature of the particles carrying the active component was changed to 530°C [catalyst (3)], the space velocity was changed to 1551/hour and the molten salt temperature was changed to 350°C. The hot spot temperature was 424°C, the conversion of propylene was 97.9%, the yield of acrolein was 82.3%, the yield of acrylic acid was 8.4% and the total selectivity of acrolein to acrylic acid was 92.6%. Even after 1200 hours of continuous reaction, no deterioration of the reaction result was found.

Example 6

The reaction is carried out in the same manner as in Example 1, except that the average particle diameter of alumina is changed to 4.5mm (the average particle diameter of the particles carrying the active component is 5.0mm) and the calcination temperature, space velocity and molten salt temperature are respectively changed to 530°C [catalyst (4)], 1600/hour and 357°C. The hot spot temperature is 414°C, the conversion of propylene is 97.9%, the yield of acrolein is 82.5%, the yield of acrylic acid is 8.7% and the total selectivity of acrolein and acrylic acid is 93.3%, even after continuous operation for 1000 hours or more Afterwards, no deterioration in response results was found.

Example 7

The reaction was carried out in the same manner as in Example 6, except that the calcination temperature of the particles carrying the active component was changed to 540°C [catalyst (5)] and the molten salt temperature was changed to 362°C. The hot spot temperature is 443°C, the conversion of propylene is 97.7%, the yield of acrolein is 82.6%, the yield of acrylic acid is 8.8%, and the total selectivity of acrolein and acrylic acid is 93.6%, even after continuous operation for 1000 hours or longer After a period of time, no worsening of the reaction results was observed.

Example 8

The catalyst (3) prepared in 1300ml embodiment 5 is added to be 21mm and be provided with the jacket that is used to circulate the molten salt of heat transfer medium and be arranged on the catalyst bed bed and be used for measuring the thermocouple of catalyst bed temperature Stainless steel (SUS304) reaction tube, including 7% (v) of propylene, 13% (v) oxygen, 42% (v) water vapor and 38% (v) nitrogen in the air with a space velocity of 1800/hour Quickly introduce into the reaction tube, while maintaining the temperature of the molten salt at 351°C, the reaction is carried out. During the reaction, the hot spot temperature was 405°C, the conversion of propylene was 97.4%, the yield of acrolein was 81.7%, the yield of acrylic acid was 8.1%, and the overall selectivity of acrolein to acrylic acid was 92.2%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 9

The reaction was carried out in the same manner as in Example 8, except that the catalyst (4) prepared in Example 6 was used and the temperature of the molten salt was changed to 352°C. The hot spot temperature was 399°C, the conversion of propylene was 97.0%, the yield of acrolein was 83.3%, the yield of acrylic acid was 7.2%, and the total selectivity of acrolein and acrylic acid was 93.3%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 10

The reaction was carried out in the same manner as in Example 8, except that the catalyst (5) prepared in Example 7 was used and the temperature of the molten salt was changed to 362°C. The hot spot temperature was 428°C, the conversion of propylene was 97.1%, the yield of acrolein was 82.1%, the yield of acrylic acid was 8.5% and the total selectivity of acrolein and acrylic acid was 93.3%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 11

423.8 g of ammonium molybdate and 2.02 g of potassium nitrate were dissolved in 3000 ml of distilled water under stirring and heating to obtain a solution (A). Separately, 302.7 g of cobalt nitrate, 162.9 g of nickel nitrate and 145.4 g of iron nitrate were dissolved in 1000 ml of distilled water to obtain a solution (B). 164.9 g of bismuth nitrate was dissolved in 200 ml of distilled water acidified with 25 ml of concentrated nitric acid to obtain a solution (C). After mixing solutions (B) and (C) together, the resulting solution was dropped into solution (A) under vigorous stirring.

The thus-obtained suspension was dried with a spray drier, and then calcined at 440° C. for 3 hours to obtain 570 g of calcined powder. 200 g of this powder was mixed with 10 g of crystalline cellulose as a molding aid.

Add 300 g of alumina carrier with an average particle diameter of 5 mm into the drum granulation coater. Then, 210g of the above-mentioned prepared mixture and 90g of 33% glycerol aqueous solution as a binding agent were added simultaneously in the drum granulation coating machine, and the mixture was carried on the carrier, thus obtaining a catalyst loading ratio of 40 % (wt) of active ingredient-loaded particles.

The particles carrying the active component were dried at room temperature for 15 hours, and then calcined at 540° C. for 5 hours in an air stream to obtain the catalyst (6) of the present invention. The average particle diameter of the catalyst thus prepared was 5.5 mm, and the atomic ratio of the catalytically active components other than oxygen was as follows: Mo=12:Bi=1.7:Ni=2.8:Fe=1.8:Co=5.2:K=0.1. oxidation reaction

The catalyzer (6) that 1900ml above-mentioned preparation is added is that average internal diameter is 27mm and is provided with the stainless steel ( SUS304) reaction tube. A mixed gas comprising 7% (v) propylene, 13% (v) oxygen, 30% (v) water vapor and 50% (v) nitrogen was introduced into the reaction tube at a space velocity of 1500/hour while maintaining the temperature of the molten salt at The reaction was carried out at 347°C. During the reaction, the hot spot temperature was 443°C, the conversion of propylene was 97.2%, the yield of acrolein was 84.9%, the yield of acrylic acid was 6.9% and the overall selectivity of acrolein to acrylic acid was 94.4%. Even after 2200 hours of continuous reaction, no deterioration of the reaction result was found. Example 12

The reaction was carried out in the same manner as in Example 11, except that the space velocity was changed to 1300/hour and the molten salt temperature was changed to 346°C. The hot spot temperature was 453°C, the conversion of propylene was 98.1%, the yield of acrolein was 84.8%, the yield of acrylic acid was 7.4%, and the overall selectivity of acrolein to acrylic acid was 94.0%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 13

The reaction was carried out in the same manner as in Example 11, except that the space velocity was changed to 1800/hour and the molten salt temperature was changed to 349°C. The salt point temperature is 444°C, the conversion of propylene is 96.7%, the yield of acrolein is 84.3%, the yield of acrylic acid is 6.9% and the total selectivity of acrolein and acrylic acid is 94.3%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 14

The reaction was carried out in the same manner as in Example 11, except in the same manner as in Example 11, but using 150 g of precalcined powder, 300 g of an alumina carrier with an average particle size of 6.0 mm and a supported active component with a particle size of 6.3 mm To prepare the [catalyst (7)] of the present invention, the temperature of the molten salt was also changed to 360°C. The hot spot temperature was 443°C, the conversion of propylene was 94.3%, the yield of acrolein was 84.1%, the yield of acrylic acid was 6.1% and the total selectivity of acrolein to acrylic acid was 95.6%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

The preparation of embodiment 15 catalyst

450 g of ammonium molybdate and 15.3 g of cesium nitrate were dissolved in 3000 ml of distilled water under stirring and heating to obtain a solution (A). Separately, 456 g of cobalt nitrate and 238 g of ferric nitrate were dissolved in 1500 ml of distilled water to prepare a solution (B). 190 g of bismuth nitrate was dissolved in 200 ml of distilled water acidified with 30 ml of concentrated nitric acid to prepare a solution (C). Solutions (B) and (C) are mixed together, and the resulting solution is dropped into solution (A) under vigorous stirring to obtain a suspension. After the suspension was dried with a spray dryer, it was pre-calcined at 460° C. for 5 hours to obtain 580 g of a pre-calcined powder. Then 300 g of the pre-calcined powder was loaded on the alumina carrier with an average particle diameter of 4 mm in the same manner as in Example 1 to obtain active component-carrying particles with a catalyst loading rate of 50% (wt).

The particles carrying the active component were dried at room temperature for 15 hours, and then calcined at 520° C. for 5 hours in an air stream to obtain the catalyst (8) of the present invention. The catalyst thus prepared had an average particle diameter of 4.4 mm, and the atomic ratio of the catalytically active components other than oxygen was as follows: Mo=12:Bi=1.8:Fe=2.8:Co=7.4:Cs=0.4. oxidation reaction

692ml of the above-mentioned prepared catalyst (8) is added with an average internal diameter of 21.4mm and is provided with a jacket for circulating molten salt as a heat transfer medium and is arranged on the catalyst bed for measuring the stainless steel (SUS) thermocouple of the catalyst bed temperature. 304) reaction tube. A gas mixture comprising 6% (v) tert-butanol, 13% (v) oxygen, 3% (v) water vapor and 78% (v) nitrogen was introduced into the reaction tube at a space velocity of 1200/hour while maintaining the temperature of the molten salt The reaction was carried out at 355°C. During the reaction, the hot spot temperature was 404°C, the conversion rate of tert-butanol was 100%, the yield of methacrolein was 81.5%, the yield of methacrylic acid was 1.9% and the ratio of methacrolein to methacrylic acid The overall selectivity was 83.4%. Even after the reaction was continued for 1000 hours or more, no deterioration of the reaction result was found.

Example 16

The catalyzer (8) of 692ml above-mentioned preparations is introduced into the stainless steel ( SUS 304) reaction tube. A mixed gas comprising 6% (v) isobutene, 12% (v) oxygen, 9% (v) steam and 73% (v) nitrogen is introduced into the reaction tube at a space velocity of 1200/hour while maintaining the temperature of the molten salt at 350°C for the reaction. During the reaction, the hot spot temperature was 389°C, the conversion rate of isobutylene was 99.2%, the yield of methacrolein was 80.9%, the yield of methacrylic acid was 1.7% and the total amount of methacrolein and methacrylic acid The selectivity was 83.3%, and even after continuous reaction for 1000 hours or more, no deterioration of the reaction result was found.

Claims (3)

1. catalyst that is used to produce unsaturated aldehyde and/or unsaturated acids, it is characterized in that, carried the catalyst of holding by catalytic active component being carried be held on the carrier and calcine, the average grain diameter of the catalyst that obtains is 4-16mm, the average grain diameter of carrier is 3-12mm, this carrier comprises at least a material, it is selected from water, HMW adhesive and polyhydroxy-alcohol, calcining heat be 500-600 ℃ and catalytic active component to be loaded in amount on the carrier be 5-80% (wt) [weight of (weight of catalytic active component)/catalytic active component weight+vehicle weight+intensity improver)], and have the composition that catalytic active component has following formula (1) expression:

Mo _aBi _bNi _cCo _dFe _fY _gZ _hO _x (1)

Y represents to be selected from least a element among Sn, Zn, W, Cr, Mn, Mg, Sb and the Ti in the formula; Z represents to be selected from least a element among K, Rb, Tl and the Cs; Represent the atomicity of Mo, Bi, Ni, Co, Fe, Y, Z and O respectively with a, b, c, d, f, g, h and x, if a=12, b=0.1-7, c+d=0.5-20, f=0.5-8, g=0-2, h=0-1, x is a value that changes with the metal component oxidizability so.

2. method that is used to produce unsaturated aldehyde and unsaturated acids, be to carry out gas phase catalytic oxidation reaction by being selected from least a compound in propylene, isobutene and the tertiary alcohol and the gas of oxygen molecule or oxygen-containing molecules, generate corresponding unsaturated aldehyde and/or unsaturated acids, it is characterized in that using the described catalyst of claim 1.

3. by the method for claim 2, it is characterized in that catalyst is added every pipe in the multitubular reactor of fixed-bed type, form a beds.